Electromechanical actuators are today used for a large variety of applications. The use of bimorph element has been very attractive due to its ability to provide motion in two dimensions. Such motion patterns are particularly suitable for different motor applications. A typical way to build the bimorph elements is to use multilayer techniques with a large number of internal electrodes. Typical examples of such actuators, based on piezoelectric materials, are to be found e.g. in the U.S. Pat. Nos. 6,337,532, 6,798,117, 7,335,325 and the published international patent application WO2007/099043.
In order to activate a multilayer bimorph, the internal electrodes have to be provided with suitable voltages. A common way to arrange for this is to let the internal electrodes reach the surface of the bimorph and provide a termination stripe at the surface of the bimorph. In the embodiments illustrated in the above mentioned documents, terminations of internal phase electrodes are provided at one side of the bimorph, whereas terminations of internal ground electrodes are provided at the opposite side. Suitable voltage sources are then electrically connected to the different terminations. In such a way) the internal electrodes are supplied with suitable voltages for creating electrical fields within the piezoelectric material, which in turn causes the piezoelectric material to present changes in geometrical dimensions.
In many applications, the actuators have to be very small, and the small size generally makes electrical connections more difficult to realize, at least in a manner which is suitable for industrial production. The terminations have typically to be provided by two consecutive manufacturing steps, one for each side of the actuator and provision of electrical connection typically has to involve a turning of the tiny actuators. High demands on geometrical precision and accuracy render relatively high production costs.